Its political director Sir Geoffrey Adams expressed the Government’s “horror” at the continued violence and demanded Syria's co-operation in repatriating the bodies and evacuating the wounded journalists.

Syrian forces murdered Colvin after pledging to kill "any journalist who set foot on Syrian soil".

Now communication between Syrian Army officers intercepted by Lebanese intelligence staff has revealed that direct orders were issued to target the makeshift press centre in which Colvin had been broadcasting.

If journalists were successfully killed, then the Syrians were told to make out that they had died accidentally in firefights with terrorist groups, the radio traffic revealed.

Just before she died, Colvin had appeared on numerous international broadcast networks including the BBC and CNN to accuse Syrian dictator Bashar Al-Assad's forces of murder'.

Jean-Pierre Perrin, a journalist for the Paris-based Liberation newspaper who was with Colvin in Homs last week, claimed they had been told that the Syrian Army was "deliberately" going to shell their centre.

Mr Perrin said: "A few days ago we were advised to leave the city urgently and we were told: 'If they (the Syrian Army) find you they will kill you'.

"I then left the city with the journalist from the Sunday Times but then she wanted to go back when she saw that the major offensive had not yet taken place."

Mr Perrin, who headed to Beirut from Homs, said the Syrians were "fully aware" that the press centre was broadcasting direct evidence of crimes against humanity, including the murdering of women and children.

"The Syrian Army issued orders to 'kill any journalist that set foot on Syrian soil'."

It was in Beirut, the capital of Lebanon, that Mr Perin received news of the intercepted Syrian Army radio traffic.

The Syrians knew that if they destroyed the press centre, then there would be "no more information coming out of Homs", said Mr Perrin.

Mr Perin said the centre had a limited electricity supply and internet access, thanks to a generator. This made it a privileged location' compared to the rest of the decimated city.

In her broadcasts on Tuesday night, Colvin had accused the Syrian Army of perpetrating the "complete and utter lie that they are only targeting terrorists." Describing what was happening as "absolutely sickening", Colvin said: "The Syrian army is simply shelling a city of cold, starving civilians."'

Other sources in Damascus confirmed that Syrians, including senior Army officers and Al-Assad himself, would have been able to watch Colvin's broadcasts.

Syrian authorities however have claimed they were not aware the journalists had entered the country.

“The authorities had no information that the two journalists had entered Syrian territory,” Adnan Mahmud told AFP.

Mr Mahmud said that he had asked “specialised authorities in Homs to look for them (Colvin and Ochlik).” He did not acknowledge whether they were dead or alive.

“The ministry urges all foreign journalists who entered Syria illegally to report to the nearest immigration office to legalise their presence,” he added.

Frederic Mitterrand, the French culture minister, said Colvin and Ochlik had been "targeted and tried to flee the bombardment", and eyewitnesses in Homs said were killed as they fled the centre.

Nicolas Sarkozy, the French president said of the attacks: "That's enough now. This regime must go and there is no reason that Syrians don't have the right to live their lives and choose their destiny freely. If journalists were not there, the massacres would be a lot worse."

Reporters working in Homs feared the Army had "locked on" to their satellite phone signals and targeted the buildings they were coming from.

Abu Abdu al-Homsi, an opposition activist, confirmed that the Army had cut phone lines into the city and were bombing any buildings where they detected mobile phone signals.